Douglas, AZ planting zone & frost dates
Douglas is in USDA hardiness zone 8a. The last spring frost usually comes around March 18 and the first fall frost around November 13, for a growing season of about 235 days.
Planting calendar for Douglas
Dates are counted from the average last spring frost (March 18) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Jan 21 – Feb 4 Transplant outdoors: Mar 25 – Apr 1 |
| Peppers | Start seeds indoors: Jan 7 – Jan 21 Transplant outdoors: Apr 1 – Apr 8 |
| Eggplant | Start seeds indoors: Jan 7 – Jan 21 Transplant outdoors: Apr 1 – Apr 8 |
| Broccoli | Start seeds indoors: Jan 7 – Jan 21 Transplant outdoors: Feb 18 – Mar 4 |
| Cabbage | Start seeds indoors: Jan 7 – Jan 21 Transplant outdoors: Feb 18 – Mar 4 |
| Onions (sets) | Plant outdoors: Feb 18 – Mar 4 |
| Peas | Sow outdoors: Feb 4 – Feb 18 |
| Spinach | Sow outdoors: Feb 4 – Feb 18 |
| Lettuce | Sow outdoors: Feb 18 – Mar 4 |
| Carrots | Sow outdoors: Feb 18 – Mar 4 |
| Potatoes | Plant outdoors: Feb 18 – Mar 4 |
| Beans | Sow outdoors: Mar 25 – Apr 1 |
| Sweet corn | Sow outdoors: Mar 25 – Apr 1 |
| Cucumbers | Sow outdoors: Mar 25 – Apr 1 |
| Squash & zucchini | Sow outdoors: Mar 25 – Apr 1 |
| Basil | Start seeds indoors: Feb 4 – Feb 18 Transplant outdoors: Mar 25 – Apr 1 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 18 (8 weeks before the average first fall frost on Nov 13).
Useful for zone 8a gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Feb 27 | Mar 18 | Apr 12 |
| First 32°F frost in fall is before | Nov 30 | Nov 13 | Oct 27 |
How to read it: in spring there is a 10% chance of a frost after April 12, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 27. A hard freeze (28°F) usually ends around February 27.
Hardiness zone by ZIP code in Douglas
- 85607 zone 8a
- 85608 zone 8a
- 85655 zone 8a
Nearby cities
- Sierra Vista Southeast zone 8b, last frost Apr 5
- Sierra Vista zone 8b, last frost Apr 5
- Vail zone 9a, last frost Jan 26
- Nogales zone 8b, last frost Mar 20
- Rio Rico zone 8b, last frost Apr 16
- Tanque Verde zone 9a, last frost Jan 26
- Green Valley zone 9a, last frost Feb 25
- Sahuarita zone 9a, last frost Feb 25
Questions
What growing zone is Douglas, AZ?
Douglas is in USDA Plant Hardiness Zone 8a (average extreme winter low 10°F to 15°F), according to the USDA 2023 map.
When is the last frost in Douglas?
The average last spring frost (32°F) in Douglas is March 18. There is still a 10% chance of frost until April 12.
When can I plant tomatoes in Douglas?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Mar 25 – Apr 1. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Douglas, AZ (USC00022659), 0.6 km (0.4 mi) from the city center, elevation 1231 m, based on 17 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.